EP 0549314 B1 19980715 - Enhanced fidelity reproduction of images by hierarchical template matching
Title (en)
Enhanced fidelity reproduction of images by hierarchical template matching
Title (de)
Verbessertes Drucken von Bildern, durch hierarchischen Vergleich mit Standardmuster
Title (fr)
Réproduction d'images en haute fidélité par comparaison à des motifs standards, de manière hiérarchique
Publication
Application
Priority
US 81155091 A 19911220
Abstract (en)
[origin: EP0549314A1] The contour fidelity of reproduction of images is enhanced by matching groups of pixels with templates based on a hierarchical set of patterns. This is accomplished by isolating a symmetrical window of pixels in the image including a central pixel (220,222,224) and matching the groups of pixels in the window with hierarchical templates (226,228). Enhancement values for the central pixel are provided based on the results of the comparison. Windows are formed so that each pixel in the image is a central pixel for at least one window. The hierarchical set of patterns is developed so that each pattern in the hierarchy is a combination of an extension pattern and the pattern immediately below it in the hierarchy. This significantly reduces the hardware requirements for implementation of the technique. Templates are developed by creating horizontal, vertical, reversed and inverted permutations of each pattern in the set. Correctable pixel locations are identified for each template (230), and the central pixel receives enhancement values when it is in the correctable location of at least one template (232). In an microaddressable printer, overscanning and increased clock frequency provide multiple segments for representing each pixel, and spot width compensation allows multiple intensity levels for each segment. <IMAGE>
IPC 1-7
IPC 8 full level
B41J 2/44 (2006.01); B41J 2/485 (2006.01); G06K 15/00 (2006.01); G06T 7/60 (2006.01); H04N 1/23 (2006.01); H04N 1/409 (2006.01)
CPC (source: EP US)
G06K 15/00 (2013.01 - EP US)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0549314 A1 19930630; EP 0549314 B1 19980715; DE 69226249 D1 19980820; DE 69226249 T2 19990121; JP 3490729 B2 20040126; JP H05316349 A 19931126; US 5329599 A 19940712
DOCDB simple family (application)
EP 92311669 A 19921221; DE 69226249 T 19921221; JP 33314592 A 19921214; US 14662993 A 19931029